Production of printed cellulose derivative textile materials



United States Patent PRODUC'IIGN OF PRINTED CELLULOSE DERIVATIVE TEXTILE MATERIALS Henry Charles ()lpin and Tom Jackson, Spondon, near crby, England, assignors to British Cclauese Limited, a corporation of Great Britain No Drawing. Application June 27, 1951,

Serial No. 233,937 x Claims priority, application Great Britain July 10, 1950 Claims. (Cl. 8--63) This invention relates to the production of coloured textile materials consisting of or containing fibres of cellulose acetate or other cellulose ester of a carboxylic acid or a cellulose ether. It is more particularly concerned with the production of coloured pattern effects on such materials.

Very satisfactory coloured pattern effects can be produced on textile fabrics consisting of or containing cellulose acetate fibres by printing with acid dyes in aqueous ethyl alcohol containing a thiocyanate. In this connection reference may be made to U. S. Patents Nos. 2,428,836 and 2,514,410. The colourations so obtained have the especial merit of very good fastness to washing. We have observed, however, that many otherwise useful dyestuffs, at the concentration required for the production of full or very full shades, do not remain in solution in the aqueous alcohol containing thiocyanate when cold. This is possibly due to the salting out action of the thiocyanate. We have further observed that when two or more printing pastes are applied in such a way that one falls at least in part upon another there is a tendency for the printed fabric to be unduly weak. Such overprinting is quite common in the textile printing art, as for example, when a fine line pattern in black or other dark shade is superimposed upon a brightly coloured pattern. We believe that this weakness is due to the high content of thiocyanate on the fabric at the doubly printed portions. This results in such high plasticisation of the material at these portions that they are very considerably weakened. This difiiculty cannot satisfactor11y be overcome by reducing the content of thiocyanate 1n the printing pastes since if this is attempted unsatisfactory fixation of dye may result at the points where only one of the printing colours has been applied. A similar difiiculty may be experienced when printing from intaglio printing surfaces, such as those produced by photogravure methods, in which reliance is placed upon variations in the depth of the "engraving at different points on the printing surface to secure particular results. Where the engraving is deep, more thiocyanate per unit area 1s app l1ed to the material than at points where the engraving is shallow. As indicated above the thiocyanate content of the printing paste must be sufiicient to ensure adequate fixation of colour at those points where the depth of engraving is at minimum.

In accordance with the present invention, in printing textile fabrics or other textile materials consisting of or containing cellulose acetate fibres or other cellulose esteror other with acid or other dyes (or with compounds convertible into dyes on the material both being hereinafter referred to as colouring agents) and using thiocyanate to assist fixation of the dye or other compound, the material is first impregnated with the thiocyanatc and then, while carrying the latter, is printed with the dye in a liquid medium substantially free from thiocyanate. In this way the presence of sufiicient thiocyanate at any point of the material to fix satisfactorily the colour can be ensured without at the same time leading to such high local concentrations of thiocyanate as might unduly weaken the material undergoing printing. The proportion of thiocyanate at any point on the material is determined by the initial impregnation and is independent of the proportion of printing paste applied at the same oint. Moreover, since the printing composition need not con 2,699,373 Patented Jan. 11, 1955 ice tain thiocyanate, it is possible to use dyes of kinds and/or at concentrations which could not be used in compositions containing thiocyanates.

In the term printing we include not only the conventional methods of applying a composition locally to a fabric by means of blocks, engraved rollers, or stencils, but also the all-over application of a composition by any method in which the required proportion of composition is applied to the material and left thereon. Thus we include all-over application by means of a plain or engraved roller arranged to transfer a predetermined proportion of printing composition from a supply of the latter to the textile fabric. Again, we include application of a predetermined proportion of a composition by spraying. We do not, however, include in the term printing application of the composition by those padding methods in which the material is allowed to take up or has applied thereto a greater proportion of composition than is desired and in which the excess is thereafter removed, as for example by squeezing. This is of course the procedure in the case of the conventional pad mangle.

The invention is of particular value in the case of textile materials consisting of or containing cellulose acetate fibres and will be more particularly described with reference to the treatment of such materials.

In carrying out the new colouring process various watersoluble thiocyanates may be employed, for example, the thiocyanates of alkali metals or ammonia or of the alkaline earth metals or of magnesium or zinc. Very good results can be obtained when ammonium thiocyanate is incorporated in the proportion of from 3% to 7% and particularly from 4% to 6% based on the weight of the textile material. Greater or less proportions may, however, be employed, for example proportions ranging from as low as 1 or 2% up to as high as 8 or 10%. Other thiocyanates may be employed in chemically equivalent proportions. The incorporation of the thiocyanate in the textile material is conveniently effected by mechanically impregnating the material with an aqueous solution of the thiocyanate, the concentration of the latter and the proportion of liquid left on the material being such as to incorporate the desired proportion of thiocyanate in the material. The mechanical impregnation may be effected by means of a padding mangle. After impregnation with the aqueous solution the material is preferably dried.

Various dyes or compounds convertible into dyes may be used in the new process. Examples are the following:

1. Acid dyes having direct aflinity for W001, including both dyes which have no affinity for cellulose acetate when applied thereto as simple aqueous dye baths as well as acid dyes which do have more or less affinity for cellulose acetate under those conditions. Examples of such acid dyes are:

Croceine Scarlet 388 Colour Index No. 277) Brilliant Alizarin Light Blue FFG (an acid anthraquinone 2. Acid dyes containing chromium or other metal in complex combination, for example, chromium compounds of sulphonated ortho-hydroxy-azo dyes. Dyes of this kind are available under the trade names Neolan and Palatine Fast. An example of such a dye is Neolan Orange G (a chromium-containing azo dye).

3. Acid sulphuric esters of dyes containing hydroxyalkyl groups, including products of this kind which have direct affinity for cellulose acetate when applied as a simple aqueous dye bath.

4. Direct cotton colours, more especially such as are capable of dyeing wool from an acid bath; an example of such a dye is Chrysophenine G (Colour Index No. 365.).

5. Mordant dyes in conjunction with a suitable compound of a mordant metal, for example, chromium ace. tate.

6. Water-insoluble dyes, including such as have direct affinity for cellulose acetate when applied as an aqueous dispersion.

7. Esters of leuco compounds of vat dyes with dior poly-basic acids, particularly the sulphuric esters.

8. Vat dyes, either in reduced form or in conjunction with a reducing agent, particularly a formaldehyde sulphoxylate. The latter may be'used in conjunction with one of the organic bases referred to in our copending U. S. application S. No. 221,125, filed April 14, 1951.

9. Compounds which can be converted to a dye upon the material. Examples are oxidisable amines, such as anlline or para-amino-diphenylamine applied in conjunction with chlorates or other suitable oxidising agents. Further examples are azo dye components, for example, diazotisable amines, azo coupling components, and stabilised diazo compounds, for example, diazo compounds which have been stabilised as diazoamino compounds by reaction with suitable amines, especially amines containing saltformmg groups, e. g. sarcosine (methylamino-acetic acid), methyl taurine (methylaminoethane sulphonic acid), 4 sulpho 2 aminoor 4 sulpho 2 methylamino benzoic acid, and 5 sulpho 2 methyl aminoor5 sulpho 2 ethylamino benzoic acid. These diazoammo compounds may be applied in conjunction with enolic coupling components and an organic base volatile in steam as more particularly described in our co-pending U. S. application No. 233,936 of even date, now abandoned.

The dyes or other compounds referred to above may be applied to the thiocyanate-bearing material in the form of aqueous or other solutions or dispersions. These may be suitably thickened according to the requirements of the particular printing method utilised for their application. Aqueous solutions may, for example be thickened with gum tragacanth, gum arabic, British gum or other water-soluble gums. Solutions in aqueous alcohols may very advantageously be thickened by means of methyl cellulose.

The liquid medium carrying the dye or compound convertible into a dye may be wholly aqueous in character or it may consist in part of water and in part of an organic liquid miscible with water. Such organic liquids may be alcohols, ketones, esters or ethers and may be compounds containing 2 or more atoms or groups of the kind commonly referred to as polar. Thus it may be a compound containing a hydroxy group together with a polar group or atom of another kind, for example a keto group -CO--, an ester group COO, an ether oxygen -O-- or a halogen atom.

Water-miscible alcohols, for example, ethyl alcohol, methyl alcohol or a propyl or butyl alcohol, have been found particularly useful as the organic liquid content of the liquid medium. Other water-miscible liquids which may be used are acetone, methyl-ethyl ketone, diacetonealcohol, partial carboxylic esters of aliphatic dior polyhydric alcohols, e. g. glycol monoacetate and glycerol diacetate, partial ethers of aliphatic dior poly-hydric alcohols, e. g. glycol monomethyl or monoethyl ether, esters of hydroxy-carboxylic acids, e. g. ethyl lactate, halogen hydrins, e. g. ethylene chlorhydrin or propylene chlorhydrin, water-miscible ethers, e. g. ethylene methylene ether or diethylene glycol, and ether-esters, for example glycol monomethyl ether acetate.

In the case of mixtures of water with a water-miscible organic liquid, the best proportion of the latter depends upon the particular organic liquid which is being employed. The mixture of water and organic liquid is preferably one capable of swelling the cellulose acetate fibres but without, of course, damaging them. Thus, when using water-miscible alcohols, for example ethyl, methyl or proyl alcohols, the latter may constitute from 50% to 75% by weight, particularly 60% to 70% of the water and alcohol together. Many of the other liquids enumerated above are solvents for cellulose acetate, and they should be used in lower proportions than indicated above in connection with the alcohols. For instance, it is not usually necessary or desirable to exceed about 25% in the case of diacetone alcohol, glycol monomethyl ether acetate, or ethyl lactate. A lower proportion may be used, but in general a proportion of at least is desirable for good results.

Particularly good results can be obtained by applying the dye or compound convertible into a dye in aqueous methyl-, ethyl, or propyl-alcohol thickened with a methyl cellulose in the manner described in U. S. Patents Nos. 2,514,410 and"2,514,4ll.

An addition of urea to the printing composition (whether the liquid medium of the printing composition is wholly aqueous or comprises organic liquid) is frequently of advantage and often leads to production of colourations of better colour value than can otherwise be secure. Thus, urea can be employed in a proportion of from 5 to 15% based on the weight of the printing composition.

After the thiocyanate-impregnated material has been printed with the dye or compound convertible into the dye in the manner indicated above, it is preferably steamed and either simply washed and finished or given any such treatment as may be necessary for bringing the dye to its final form on the material, or indeed, for forming the dye on the material in the case where compounds convertible into dyes have been applied. Thus, when esters of leuco vat dyes have been applied the material may be given an acid oxidising treatment in order to regenerate the parent vat dye. For example treatment with an acidific nitrite or chromate solution may be employed or a simple acid treatment in case a nitrite or like compound which becomes an elfective oxidising agent on acidification has been incorporated in the printing composition. When vat dyes are employed an oxidising treatment is likewise usually necessary; this may consist of an alkaline oxidising treatment for example, with sodium percarbonate or sodium perborate. In the case of applying azo dye components the necessary aftertreatment depends upon the particular materials employed. Thus, where a diazotisable amine and a coupling component have been applied together the treatment may be an acidified nitrite treatment. Again, when using coupling components in conjunction with diazo cornpounds stabilised as diazo-amino-compounds, an acid steaming treatment may be used.

Diazo compounds stabilised as diazo-amino compounds may be applied in conjunction with enolic coupling components and an organic base volatile in steam as more particularly described in co-pending U. S. application No. 233,936 of even date. In this case decomposition of the diazo-amino compound with regeneration of the diazo compound and coupling of the latter with the coupling component can be efiected by a steamlng treatment without the use of acid. 1

The invention specifically includes the application of the following treatments to a cellulose acetate textile fabric, the printing being either uniformly all over or in a pattern:

(a) Pad with an aqueous thiocyanate solution, dry and print with a thickened aqueous solution of an acid dye, having afiinity for cellulose acetate or not, followed by steaming. The printing composition may contain urea.

(b) Pad with an aqueous thiocyanate solution, dry and print with a solution of an acid dye in a mixture ofwater with ethyl alcohol or other water-miscible organic liquid, thickened with water-soluble methyl cellulose, steam, and wash off. The printing composition may contain urea.

(c) Pad with an aqueous thiocyanate solution, dry and print with a solution of a mordant dye and a chromium salt in a mixture of water with ethyl alcohol or other water-miscible organic liquid thickened with methyl cellulose, steam and wash off.

(d) Pad with an aqueous thiocyanate solution, dry and print with a solution of sulphuric ester of a leuco vat dye in a mixture of water with ethyl alcohol or other watermiscible organic liquid thickened with methyl cellulose, followed by steaming and oxidation with acidified nitrite. The printing composition may contain urea.

(e) Pad with an aqueous thiocyanate solution, dry, and print with a thickened aqueous liquid containing unreduced vat dye, sodium formaldehyde sulphoxylate, and an organic or inorganic base and then steam and oxidise. The printing composition may contain urea.

(f) Pad with an aqueous thiocyanate solution, dry, and print with a thickened aqueous preparation containing unreduced vat dye, sodium formaldehyde sulphoxylate, and a hydroxy-alkylamine, e. g. monoethanolamine, and thereafter steam and oxidise.

(g) Pad with an aqueous thiocyanate solution, dry-and print with aqueous ethyl alcohol thickened with methyl cellulose and containing an azo coupling component, a d azo compound which has been stabilised by conversion A cellulose acetate woven fabric is paddedwith an aqueous solution of ammonium thiocyanate of 8% strength so that the material retains from 50 to 75% ofits weight of the solution. Itis thereafter dried and printed with a composition of the following constitution:

Methylatedspirit ccs 65 Aqueous solution of methyl cellulose of 4% strength u grams 35 CroceineScarlet 3B8 do 2.5

The methyl-cellulose is a water-soluble product having a viscosity of400 to 1000 centipoises as measured in 2% aqueous solution at 25 C. The printed material is then steamed for 40 minutes, at 225 F., washed off in cold Water and soaped at 60 C. ina 1 /2 gram per litre soap solution. It is then dried andfinished. A scarlet print of verygood fastness to washing is thus obtained.

In this example the Croceine Scarlet3BS may bereplaced by Brilliant Alizarin Light Blue FFG, Solway Green G150, Neolan Orange G300, Artol Blue 8 or Chrysophenine G.

Example II Cellulose acetate textile fabric is padded with ammonium thiocyanate and dried as described in Example I and is thereafter printed with a paste made as follows: 2.5 grams of Solway Green G150 is dissolved by Warming in 37.5 grams of water containing 10 grams of urea and the solution is then added to 50 grams of a 25% aqueous solution of gum nafka. The material is then steamed, washed off, and soaped in the manner described in Example I.

A green print of excellent fastness to washing is obtained.

In this example the Solway Green G may be replaced by other of the acid or direct cotton dyes referred to above.

Example III A fabric composed of cellulose acetate rayon is padded with a. solution of ammonium thiocyanate and dried, conditions being arranged so that of ammonium thiocyanate on the weight of fabric is applied. It is then printed with a paste made up as follows:

Parts Dye obtained by coupling diazotised p-nitraniline with the sodium salt of the sulphate ester of ethylhydroxyethylaniline 1 Methylated spirit 75 Methyl cellulose 12% aqueous paste 24 as After printing and drying, the fabric is steamed for 1 hour at 220 F., washed off, and dried. A bright red print is thereby obtained.

Example IV A fabric composed of cellulose acetate rayon is padded with a solution of ammonium thiocyanate and dried, con ditions being arranged so that 5% of the thiocyanate on the weight of goods is applied. It is then printed with a paste of the following composition:

The chromium acetate is added immediately before printing. After 'printing and drying, thefabric isstear'n'ed for 1 hour at 220 F., washed off, and-dried; A blue print of excellent fastn'ess to washing is thereby obtained.

Example V A fabric composed ofcellulose acetate rayon is padded with a solution ofsodiumthiocyanate and dried, conditions beingarranged so'that 5% of sodium thiocyanate on the weight of fabric is applied. It is then printed with a paste made up as follows:

Parts Azo dye from diazotised p -nitran'iline and di(oxyethyl) m-chloraniline (10% paste) Methyl cellulose 12% aqueous'paste 40 Water 40 135 After printing and drying, the fabric is steamed .1 hour zit-220 F., washed off, and dried- A full. scarlet print is thereby obtained.

Example VI A cellulose acetate fabric prepadded as described in Example III so as to carry 5% ammonium thiocyanate is printed with the following paste:

Parts Soledon Jade Green XS (sulphuric ester of leuco dimethoxy dibenzanthrone) 2 Methylated spirit 74 Methyl cellulose 12% aqueous paste 24 After printing and drying, the fabric is steamed for 1 hour at 220 F., washed, and then oxidised for 20 seconds at 60 C. in an aqueous bath containing 1.5 grams per litre sodium nitrite and 20 grams per litre sulphuric acid. It is then re-washed, treated in 1 gram per litre soap solution at 60 C. for 20 minutes, rinsed, and dried. A fast green print is thereby obtained.

Example VII A cellulose acetate fabric prepadded as described in Example V so as to carry 5% sodium thiocyanate is printed with the following printing paste:

hour at 220 F., washed in cold water, oxidised in 1 gram per litre sodium percarbonate for 15 minutes at 60 C., washed again, soaped lightly, and dried. A red print is thereby obtained.

Fabrics or other materials treated in accordance with the invention may consist wholly of cellulose acetate fibres, whether continuous filaments or staple fibres, or in part of such fibres and in part of other materials, for example, cotton, regenerated cellulose, wool or silk. These other materials may acquire colour at the same time as the cellulose acetate, according to the affinity of the material for the particular dye under the particular conditions employed.

While the invention has been described more particularly with reference to the treatment of cellulose acetate textile materials it may be applied in the treatment of textile materials of other cellulose esters of carboxylic acids or to materials of cellulose ethers. Examples of such cellulose esters and others are cellulose acetate propionate, cellulose acetate butyrate, cellulose propionate, and ethyl and benzyl cellulose.

In accordance with a modification of the invention, instead of applying the composition containing the dye, or compound convertible into a dye, to the thiocyanateimpregnated material by printing it is applied by another mechanical impregnation method, for example by padding. Thus it may be applied by a padding mangle in which the material is saturated with the dye composition and the excess over that required in the material removed by squeezing.

' Having described our invention, what we desire to secure by Letters Patent is:

1. A process of printing cellulose acetate fabric with coloring agents, which comprises uniformly impregnating said fabric with an aqueous solution of a watersoluble thiocyanatev to assist the incorporation of the coloring agents in the fabric, drying the fabric and then printing the fabric locally with at least two printing pastes containing coloring agents so that one of said pastes falls at least in part on another, said pastes being free from thiocyanate.

2. Process of printing with a coloring agent a textile fabric of a cellulose derivative selected from the group consisting of cellulose esters of carboxylic acid and cellulose ethers, which comprises uniformly impregnating said textile fabric with an aqueous solution of a watersoluble thiocyanate to assist the incorporation of the coloring agent in the fabric, the weight of thiocyanate being chemically equivalent to from 3 to 7% of ammonium thiocyanate based on the weight of the fabric, drying the impregnated fabric, and printing said fabric with a thiocyanate-free printing paste containing coloring agent, the amount of printing paste applied per unit area of the printed parts being different at different portions of the printed parts.

3. Process according to claim 2 in which the dried fabric is printed locally with at least two printing pastes containing coloring agents so that one of said pastes falls at least in part on another, said pastes being free from thiocyanate.

4. Process according to claim 2 in which the printing paste is applied by means of an intaglio surface of which the tilepth of engraving is greater at some points than at ot ers.

5. Process according to claim 2 in which said cellulose derivative is cellulose acetate.

6. Process according to claim 2, wherein the fabric is impregnated with from 3% to 7% of its weight of ammonium thiocyanate.

7. Process according to claim 2, wherein the coloring agent is an acid dye and is applied in an aqueous lower aliphatic alcohol medium and the fabric is thereafter steamed.

8. Process according to claim 2, wherein the coloring agent is an acid dye and is applied in aqueous urea solution' and the fabric is thereafter steamed.

9. Process according to claim 1, wherein the coloring agent is an acid dye and is applied in an aqueouslower aliphatic alcohol medium and the fabric is thereafter steamed.

10. Process according to claim 2, wherein the coloring agent is an acid dye and is applied in an aqueous lower aliphatic alcohol medium and the fabric is thereafter steamed.

References Cited in the file of this patent UNITED STATES PATENTS 2,133,470 Olpin Oct. 18, 1938 2,428,836 Croft Oct. 14, 1947 FOREIGN PATENTS 588,106 Great Britain May 14, 1947 285,942 Great Britain Feb. 23, 1928 599,055 Great Britain Mar. 3, 1948 299,849 Great Britain Oct. 31, 1929 

2. PROCESS OF PRINTING WITH A COLORING AGENT A TEXTILE FABRIC OF A CELLULOSE DERIVATIVE SELECTED FROM THE GROUP CONSISTING OF CELLULOSE ESTERS OF CARBOXYLIC ACID AND CELLULOSE ETHERS, WHICH COMPRISES UNIFORMLY IMPREGNATING SAID TEXTILE FABRIC WITH AN AQUEOUS SOLUTION OF A WATERSOLUBLE THIOCYANATE TO ASSIST THE INCORPORATION OF THE COLORING AGENT IN THE FABRIC, THE WEIGHT OF THIOCYANATE BEING CHEMICALLY EQUIVALENT TO FROM 3 TO 7% OF AMMONIUM THIOCYANATE BASED ON THE WEIGHT OF THE FABRIC, DRYING THE IMPREGNATED FABRIC, AND PRINTING, SAID FABRIC WITH A THIOCYANATE-FREE PRINTING PASTE CONTAINING COLORING AGENT, THE AMOUNT OF PRINTING PASTE APPLIED PER UNIT AREA OF THE PRINTED PARTS BEING DIFFERENT AT DIFFERENT PORTIONS OF THE PRINTED PARTS. 